Abstract

ARTIGO

Aromatic compounds from three Brazilian Lauraceae species

Andrea Nastri de Luca BatistaI, ^* * e-mail: andrluca@yahoo.com.br ; João Marcos Batista Junior^I; Silvia Noelí López^I; Maysa Furlan^I; Alberto José Cavalheiro^I; Dulce Helena Siqueira Silva^I; Vanderlan da Silva Bolzani^I; Sergio Massayoshi Nunomura^II; Massayoshi Yoshida^III

^IDepartamento de Química Orgânica, Instituto de Química, Universidade Estadual Paulista "Júlio de Mesquita Filho", Rua Francisco Degni, s/n, 14800-900 Araraquara - SP, Brasil

^IIDepartamento de Produtos Naturais, Divisão de Química de Produtos Naturais, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, 69083-000 Manaus - AM, Brasil

^IIICentro de Biotecnologia da Amazônia, Av. Governador Danilo de Matos Areosa, 690, 69075-351 Manaus - AM, Brasil

ABSTRACT

Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of São Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees & Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia.

Keywords: Lauraceae; Ocotea; Persea.

INTRODUCTION

The Lauraceae family comprises 52 genera and approximately 3000 species, mostly from tropical and warm subtropical regions of the world.¹ Lauraceae species present several groups of secondary metabolites, most of them aromatic, which seem to be relevant for chemotaxonomic classification in Lauraceae.²

The genus Ocotea comprises ca. 350 species. Previous phytochemical studies have revealed the presence of neolignans, benzylisoquinoline alkaloids, phenylpropanoids, flavonoids and sesquiterpenes,³ besides a variety of volatile components from its essential oils.¹Ocotea elegans is known as canela de ferro or canela preta in Brazil where it is widespread. Despite its huge distribution, the only study performed on O. elegans reports the isolation of neolignans from the stems by using countercurrent chromatography.⁴Ocotea corymbosa is popularly known as canela de corvo or canela fedorenta in Brazil and its wood is employed in the civil construction industry.⁵ Only two studies were performed on O. corymbosa; monoterpenes and sesquiterpenes as well as phytosterols were isolated from the unripe fruits³ and sesquiterpenes with calamenene skeleton were characterized from its bark.⁶ No previous studies have been performed on leaves of O. corymbosa.

Persea is a genus that comprises ca. 200 species, the most well studied of these being P. americana Mill, known as "avocado fruit". Previous phytochemical studies on avocado seeds identified various classes of natural products such as phytosterols, triterpenes,⁷ fatty acids with olefinic and acetylenic bonds,⁸ alkylfurans,⁹ dimers of flavanols,¹⁰ oligomeric proanthocyanidins¹¹ and glucosylated abscisic acids.¹²Persea pyrifolia is popularly known as maçaranduba and it is frequently employed in the furniture manufacturing industry.¹³ The only study carried out on P. pyrifolia dealt with volatile compounds from the leaves.¹⁴

As part of our on-going program devoted to phytochemical investigations on Brazilian Lauraceae species, in this work we report the isolation of an ester of the 4-O-E-caffeoylquinic acid (1) and three flavonoids (2-4) from O. corymbosa, an aromatic sesquiterpene (5) and a flavonoid (6) from O. elegans as well as four furofuran lignans (7-10) from P. pyrifolia. This is the first chemical study on the leaves of O. elegans and O. corymbosa as well as the first report of non-volatile compounds from P. pyrifolia.

EXPERIMENTAL

General

Analytical and preparative HPLC separations were performed by using stainless-steel Phenomenex Luna phenyl-hexyl (250 x 4.6 mm and 250 x 22 mm, 5 and 10 μm particle size, respectively) and Phenomenex Luna C-18 (250 x 4.6 mm and 250 x 22 mm, 5 and 10 μm particle size, respectively). Mobile phases for chromatography were prepared from HPLC grade solvents. Methanol and acetonitrile were obtained from J.T. Baker (Phillipsburg, NJ, USA) and Tedia (Fairfield, OH, USA), respectively. Water was purified in-house with a Millipore Milli-Q system (Billerica, MA, USA). The analytical HPLC separations were carried out using a Shimadzu (Kyoto, Japan) LC-10Ai pump system, a Shimadzu SIL-10Ai auto injector and a Shimadzu SPD-10Avp UV-Vis detector. The HPLC system used for preparative separations was a Varian (Walnut Creek, CA, USA) PrepStar SD-1 equipped with a Rheodyne (Cotati, CA, USA) injector with a 2 mL sample loop and a ProStar UV-Vis detector. NMR spectra were recorded on a Varian Inova 500 FT-NMR (Palo Alto, CA, USA) spectrometer operating at 500 MHz (¹H) and 125 MHz (¹³C). Chemical shifts were referenced relative to TMS or the corresponding residual solvent signals. Deuterated solvents (CDCl₃ and DMSO-d₆) were purchased from Cambridge Isotope Laboratories, Inc. (Andover, MA, USA). DCCC separations were performed using an EYELA D.C.C. - 300 (Tokyo Rikakikai CO LTD). All solvents used for column chromatography (CC) as well as for DCCC were from analytical grade. Silica gel for CC (60-200 μm) was purchased from Acros Organics (New Jersey, NJ, USA).

Plant material

The specimens O. elegans Mez. and P. pyrifolia Nees & Mart. ex Nees were collected at Fazenda Campininha, Mogi-Guaçu, SP; O. corymbosa (Meins) Mez. was collected in Araraquara, SP, Brazil. Voucher specimens of O. elegans (Moraes 06), O. corymbosa (deLuca 001) and P. pyrifolia (Lima 136) are deposited at the Herbarium of Instituto de Botânica, SP, Brazil.

Extraction and isolation of chemical constituents

In order to delineate this work, our selection criterion for the elected fractions was based on monitoring the occurrence of signals in the region of aromatic chemical shifts in the ¹H NMR spectra. For each studied species, only fractions showing aromatic signals were selected for further chromatographic separations.

The dried and powdered leaves (200 g) of O. corymbosa were sequentially extracted with hexane and methanol at room temperature (3 x 1000 mL, 3 days). The solvents were evaporated under reduced pressure. The methanolic residue (13.6 g) was suspended with methanol:water (9:1, v/v, 300 mL) and then partitioned successively with hexane, ethyl acetate and n-butanol (3 x 100 mL). The n-butanolic residue (2.0 g) was submitted to DCCC in descendent mode yielding 33 fractions (180 mL). The solvent system employed was a mixture of chloroform:methanol:water (43:37:20, v/v/v). Fractions 30 (60.0 mg) and 31 (85.0 mg) were subsequently purified by preparative HPLC, using as eluent an isocratic mixture of methanol:water (47:53, v/v), 5 mL min^-1, column: Phenomenex Luna phenyl-hexyl (250 x 22 mm, 10 μm particle size) and UV detection at λ 254 nm. This procedure yielded the compounds 1 (12.0 mg, t_R = 21.28 min), 2+3 (20.0 mg, t_R = 28.61 min) and 4 (5.0 mg, t_R = 31.53 min).

The dried and powdered leaves (50.0 g) of O. elegans were submitted to extraction with ethanol at room temperature (3 x 200 mL, 3 days). The solvent was evaporated under reduced pressure. The residue (1.23 g) was suspended with methanol:water (9:1, v/v, 50 mL) and then washed with hexane. The hydroalcoholic residue (1.0 g) was submitted to silica gel (60-200 μm) CC, eluted with a gradient of hexane, ethyl acetate and methanol affording 17 fractions (50 mL). The fraction 2 afforded compound 5 (8.0 mg). The fraction 15 (200 mg) was further purified by preparative HPLC yielding compound 6 (120 mg, t_R = 32.51 min). As eluent was used an isocratic mixture of water:acetonitrile (8:2, v/v), 12 mL min^-1, column: Phenomenex Luna phenyl-hexyl (250 x 22 mm, 10 μm particle size) and UV detection at λ 254 nm.

The dried and powdered leaves (250 g) of P. pyrifolia were sequentially extracted with hexane and methanol at room temperature (3 x 1000 mL, 3 days). The solvents were evaporated under reduced pressure. The hexanic residue (8.0 g) was suspended with methanol:water (9:1, v/v, 200 mL) and then washed with hexane. The hydroalcoholic residue (1.0 g) was submitted to silica gel (60-200 μm) CC, eluted with a gradient of hexane, ethyl acetate and methanol yielding 30 fractions (25 mL). The fractions 4-7 were pooled together and furnished compound 7 (37.0 mg). Fractions 10 (90.0 mg) and 18 (80.0 mg) were purified by preparative HPLC. As eluent was used an isocratic mixture of methanol:water (55:45, v/v), 12.0 mL min^-1, column: Phenomenex Luna C-18 (250 x 22 mm, 10 μm particle size) and UV detection at λ 254 nm. This procedure afforded the compounds 8 (11.0 mg, t_R = 35.05 min), 9 (3.0 mg, t_R = 25.43 min) and 10 (3.0 mg, t_R = 52.86 min).

By a combination of spectroscopic methods (¹H and ¹³C NMR spectra) and comparison with the literature data, the compounds were identified as follows: 4-O-E-caffeoylquinic acid methyl ester (1),¹⁵ quercetin-3-O-β-D-glucoside (2),¹⁶ quercetin-3-O- β-D-galactoside (3),¹⁶ quercetin-3-O-β-D-xyloside (4),¹⁶rel-(1R, 4S)-7-hydroxycalamenene (5),⁶rel-(2R, 3R)-dihydroquercetin-3-O-α-L-rhamnoside (astilbin) (6),¹⁷rel-(7S, 7'S, 8R, 8'R)-sesamin (7),¹⁸rel-(7S, 7'S, 8R, 8'R)-methylpiperitol (8),¹⁸rel-(7S, 7'S, 8R, 8'R)-eudesmin (9)¹⁸ and rel-(7S, 7'S, 8R, 8'R)-magnolin (10).¹⁹

RESULTS AND DISCUSSION

The present study reports the isolation of one ester of the 4-O-E-caffeoylquinic acid (1), four flavonoids (2-4 and 6), one aromatic sesquiterpene (5) and four furofuran lignans (7-10) from the leaves of three Lauraceae species from the Cerrado region of São Paulo state, Brazil (Figure 1). This is the first time that an aromatic sesquiterpene and flavonoids are reported for O. elegans, flavonoids and an ester of the 4-O-E-caffeoylquinic acid for O. corymbosa as well as furofuran lignans for P. pyrifolia.

The sesquiterpene rel-(1R, 4S)-7-hydroxycalamenene (5) isolated from O. elegans, has already been isolated from O. corymbosa.⁶ However, there are no reports regarding this compound on other Lauraceae genera.

All the flavonoids isolated are derived from quercetin (2-4) and dihydroquercetin (6) aglycones. This feature seems to be common to other Lauraceae species likewise O. elegans and O. corymbosa.

The furofuran lignans (7-10) isolated from P. pirifolia were reported previously from Nectandra, Licaria, and Litsea species.²⁰ This finding corroborates the importance of lignans and neolignans as phytochemical constituents in Lauraceae species.

The genera studied in this work encompass many species, which are difficult to identify based just on morphological features.²¹ Mistakes in botanical identification could be prevented by using the information obtained from a comprehensive analysis of the chemical profiles of the putative species.

SUPPLEMENTARY MATERIAL

NMR (¹H and ¹³C) data for the isolated compounds 1-10 are available at http://www.quimicanova.sbq.org.br, in PDF format with free access.

ACKNOWLEDGEMENTS

This work was supported by grants from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), as well as by Fundação de Amparo à Pesquisa do Estado do Amazonas research fellowship to M. Yoshida. The authors wish to thank FAPESP for providing scholarships.

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Recebido em 25/2/09; aceito em 5/8/09; publicado na web em 12/1/10

MATERIAL SUPLEMENTAR

4-O-E-caffeoylquinic acid methyl ester (1): ¹H NMR (DMSO-d₆, 500 MHz) δ: 1.92 (1H, dd, J = 3.5 and 13.5 Hz, H-2ax.), 2.10 (2H, m, H-2eq. and H-6eq.), 3.57 (1H, m, H-3), 5.01 (1H, dd, J = 5.0 and 8.5 Hz, H-4), 3.88 (1H, m, H-5), 1.76 (dd, J = 9.5 and 12,5, H-6ax.), 3.55 (1H, s, H-8), 7.02 (1H, d, J = 2.0 Hz, H-2´), 6.76 (1H, d, J = 8.5 Hz, H-5´), 6.96 (1H, dd, J = 2.0 and 8.5 Hz, H-6´), 7.37 (1H, d, J = 16.0 Hz, H-7´), 6.10 (1H, d, J = 16.0 Hz, H-8´). ¹³C NMR (DMSO-d₆, 125 MHz) δ : 73.0 (C-1), 35.0 (C-2), 69.3 (C-3), 71.0 (C-4), 67.2 (C-5), 37.2 (C-6), 173.6 (C-7), 51.8 (C-8), 125.3 (C-1'), 114.6 (C-2'), 148.5 (C-3'), 145.6 (C-4'), 115.8 (C-5'), 121.3 (C-6'), 145.1 (C-7'), 113.8 (C-8´), 165.3 (C-9´).

quercetin-3-O-β-D-glucoside (2): ¹H NMR (DMSO-d₆, 500 MHz) δ : 6.20 (1H, bs, H-6), 6.41 (1H, bs, H-8), 7.58 (1H, d, J = 2.0 Hz, H-2'), 6.84 (1H, d, J = 8.5 Hz, H-5'), 7.57 (1H, dd, J = 2.0 and 8.5 Hz, H-6'), 5.46 (1H, d, J = 7.0 Hz, H-1''), 3.58 - 3.24 (sugar H). ¹³C NMR (DMSO-d₆, 125 MHz) δ : 156.2 (C-2), 133.3 (C-3), 177.4 (C-4), 161.2 (C-5), 98.7 (C-6), 164.2 (C-7), 93.5 (C-8), 156.3 (C-9), 104.0 (C-10), 121.1 (C-1'), 115.2 (C-2'), 144.8 (C-3'), 148.4 (C-4'), 116.2 (C-5'), 121.6 (C-6'), 100.8 (C-1''), 74.1 (C-2''), 76.5 (C-3''), 69.9 (C-4''), 77.5 (C-5''), 60.9 (C-6'').

quercetin-3-O-β-D-galactoside (3): ¹H NMR (DMSO-d₆, 500 MHz) δ : 6.20 (1H, bs, H-6), 6.41 (1H, bs, H-8), 7.53 (1H, d, J = 2.0 Hz, H-2'), 6.81 (1H, d, J = 8.5 Hz, H-5'), 7.66 (1H, dd, J = 2.0 and 8.5 Hz, H-6'), 5.37 (1H, d, J = 7.0 Hz, H-1''), 3.56 - 3.28 (sugar H). ¹³C NMR (DMSO-d₆, 125 MHz) δ : 156.1 (C-2), 133.4 (C-3), 177.4 (C-4), 161.2 (C-5), 98.7 (C-6), 164.2 (C-7), 93.5 (C-8), 156.2 (C-9), 103.9 (C-10), 121.1 (C-1'), 115.2 (C-2'), 144.8 (C-3'), 148.5 (C-4'), 115.9 (C-5'), 121.9 (C-6'), 101.8 (C-1''), 71.2 (C-2''), 73.4 (C-3''), 67.9 (C-4''), 75.8 (C-5''), 60.1 (C-6'').

quercetin-3-O-β-D-xyloside (4): ¹H NMR (DMSO-d₆, 500 MHz) δ : 6.16 (1H, bs, H-6), 6.36 (1H, bs, H-8), 7.56 (1H, d, J = 2.0 Hz, H-2'), 6.84 (1H, d, J = 8.5 Hz, H-5'), 7.53 (1H, dd, J = 2.0 and 8.5 Hz, H-6'), 5.33 (1H, d, J = 7.0 Hz, H-1''), 3.31 - 2.96 (sugar H). ¹³C NMR (DMSO-d₆, 125 MHz) δ : 156.2 (C-2), 133.1 (C-3), 177.2 (C-4), 162.5 (C-5), 99.1 (C-6), 164.1 (C-7), 94.0 (C-8), 156.2 (C-9), 104.3 (C-10), 121.0 (C-1'), 116.2 (C-2'), 146.2 (C-3'), 150.1 (C-4'), 116.5 (C-5'), 121.9 (C-6'), 102.3 (C-1''), 74.5 (C-2''), 76.8 (C-3''), 70.2 (C-4''), 66.0 (C-5'').

rel-(1R, 4S)-7-hydroxycalamenene (5): ¹H NMR (CDCl₃, 500 MHz) δ : 2.64 (1H, m, H-1), 1.25 (1H, m, H-2a), 1.18 (1H, m, H-2b), 1.49 (1H, m, H-3a), 1.74 (1H, m, H-3b), 2.56 (1H, m, H-4), 6.86 (1H, s, H-5), 6.57 (1H, s, H-8), 2.12 (1H, m, H-11), 0.64 (3H, d, J = 6.5 Hz, H-12), 0.91 (3H, d, J = 6.5 Hz, H-13), 1.16 (3H, d, J = 7.0 Hz, H-14), 2.13 (3H, s, H-15). ¹³C NMR (CDCl₃, 125 MHz) δ : 32.6 (C-1), 30,8 (C-2), 21.6 (C-3), 43.1 (C-4), 130.5 (C-5), 120.6 (C-6), 151.4 (C-7), 113.0 (C-8), 142.1 (C-9), 132.2 (C-10), 31.9 (C-11), 17.3 (C-12), 21.2 (C-13), 22.2 (C-14), 15.5 (C-15).

rel-(2R, 3R)-astilbin (6): ¹H NMR (DMSO-d₆, 500 MHz) δ : 5.25 (1H, d, J = 10.0 Hz, H-2), 4.65 (1H, d, J = 10.0 Hz, H-3), 5.90 (1H, d, J = 2.0 Hz, H-6), 5.88 (1H, d, J = 2.0 Hz, H-8), 6.89 (1H, s, H-2'), 6.74 (2H, s, H-5' and H-6'), 4.04 (1H, d, J = 1.5 Hz, H-1''), 3.90 - 3.10 (sugar H), 1.05 (1H, d, J = 6.0 Hz, H-6''). ¹³C NMR (DMSO-d₆, 125 MHz) δ : 81.6 (C-2), 75.7 (C-3), 194.5 (C-4), 163.5 (C-5), 96.1 (C-6), 167.2 (C-7), 95.1 (C-8), 162.2 (C-9), 101.0 (C-10), 127.0 (C-1'), 114.8 (C-2'), 145.2 (C-3'), 145.9 (C-4'), 115.4 (C-5'), 119.0 (C-6'), 100.1 (C-1''), 70.1 (C-2''), 70.4 (C-3''), 71.7 (C-4''), 69.0 (C-5''), 17.8 (C-6'').

rel-(7S, 7'S, 8R, 8'R)-sesamin (7): ¹H NMR (CDCl₃, 500 MHz) δ : 6.77 (2H, d, J = 1.5 Hz, H-2 and H-2´), 6.71 (2H, d, J = 8.0 Hz, H-5 and H-5´), 6.70 (2H, dd, J = 1.5 and 8.0 Hz, H-6 and H-6´), 4.64 (2H, d, J = 4.0 Hz, H-7 and H-7´), 2.97 (2H, m, H-8 and H-8´), 4.15 (2H, dd, J = 7.0 and 9.0 Hz, H-9eq. and H-9´eq.), 3.78 (2H, dd, J = 4.0 and 9.0 Hz, H-9ax. and H-9´ax.), 5.87 (4H, s, O-CH₂-O). ¹³C NMR (CDCl₃, 125 MHz) δ : 135.0 (C-1 and C-1´), 106.4 (C-2 and C-2´), 147.0 (C-3 and C-3´), 147.9 (C-4 and C-4´), 108.1 (C-5 and C-5´), 119.2 (C-6 and C-6´), 85.7 (C-7 and C-7´), 54.3 (C-8 and C-8´), 71.6 (C-9 and C-9´), 101.0 (O-CH₂-O).

rel-(7S, 7'S, 8R, 8'R)-methylpiperitol (8): ¹H NMR (CDCl₃, 500 MHz) δ : 6.78 (1H, m, H-2), 6.70 (1H, dd, J = 0.5 and 8.0 Hz, H-5), 6.73 (1H, m, H-6), 4.66 (2H, m, H-7 and H-7´), 3.00 (2H, m, H-8 and H-8´), 4.17 (2H, m, H-9eq. and H-9´eq.), 3.81 (2H, m, H-9ax. and H-9´ax.), 6.83 (1H, d, J = 2.0 Hz, H-2´), 6.78 (2H, m, H-5´ and H-6´), 5.87 (2H, s, O-CH₂-O), 3.80 (3H, s, OMe-3´), 3.82 (3H, s, OMe-4´). ¹³C NMR (CDCl₃, 125 MHz) δ : 135.1 (C-1), 106.4 (C-2), 147.1 (C-3), 147.9 (C-4), 108.1 (C-5), 119.3 (C-6), 85.7 (C-7 and C-7´), 54.1 (C-8 and C-8´), 71.7 (C-9 and C-9´), 133.5 (C-1´), 109.3 (C-2´), 148.7 (C-3´), 149.2 (C-4´), 111.3 (C-5´), 118.2 (C-6´), 101.0 (O-CH₂-O), 55.9 (OMe-3´ and OMe-4´).

rel-(7S, 7'S, 8R, 8'R)-eudesmin (9): ¹H NMR (CDCl₃, 500 MHz) δ : 6.83 (2H, d, J = 1.5 Hz, H-2 and H-2´), 6.77 (2H, d, J = 8.0 Hz, H-5 and H-5´), 6.79 (2H, dd, J = 1.5 and 8.0 Hz, H-6 and H-6´), 4.68 (2H, d, J = 4.0 Hz, H-7 and H-7´), 3.03 (2H, m, H-8 and H-8´), 4.18 (2H, dd, J = 7.0 and 9.0 Hz, H-9eq. and H-9´eq.), 3.81 (2H, m, H-9ax. and H-9´ax.), 3.80 (6H, s, OMe-3 and OMe-3´), 3.82 (6H, s, OMe-4 and OMe-4´). ¹³C NMR (CDCl₃, 125 MHz) δ : 133.6 (C-1 and C-1´), 109.3 (C-2 and C-2´), 148.7 (C-3 and C-3´), 149.2 (C-4 and C-4´), 111.1 (C-5 and C-5´), 118.2 (C-6 and C-6´), 85.8 (C-7 and C-7´), 54.2 (C-8 and C-8´), 71.7 (C-9 and C-9´), 55.9 (OMe-3, OMe-3´, OMe-4 and OMe-4´).

rel-(7S, 7'S, 8R, 8'R)-magnolin (10): ¹H NMR (CDCl₃, 500 MHz) δ : 6.83 (1H, d, J = 2.0 Hz, H-2), 6.77 (1H, d, J = 8.0 Hz, H-5), 6.80 (1H, dd, J = 2.0 and 8.0 Hz, H-6), 4.69 (1H, d, J = 4.5 Hz, H-7), 3.03 (1H, m, H-8), 4.21 (1H, dd, J = 7.0 and 9.0 Hz, H-9eq.), 3.82 (1H, m, H-9ax.), 6.50 (1H, s, H-2' and H-6'), 4.67 (1H, d, J = 5.0 Hz, H-7'), 3.03 (1H, m, H-8'), 4.20 (1H, m, H-9´eq.), 3.84 (1H, m, H-9´ax.), 3.80 (3H, s, OMe-3), 3.82 (3H, s, OMe-4), 3.79 (3H, s, OMe-3' and OMe-5'), 3.76 (3H, s, OMe-4'). ¹³C NMR (CDCl₃, 125 MHz) δ : 133.1 (C-1), 109.3 (C-2), 148.7 (C-3), 149.2 (C-4), 111.1 (C-5), 118.2 (C-6), 85.7 (C-7 and C-7´), 54.1 (C-8), 71.9 (C-9), 136.8 (C-1´), 102.9 (C-2´ and C-6´), 153.4 (C-3´ and C-5´), 137.6 (C-4´), 54.4 (C-8´), 71.7 (C-9´), 55.9 (OMe-3 and OMe-4), 56.2 (OMe-3´ and OMe-5´), 60.8 (OMe-4´).

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